This invention relates to temperature controlled displays, especially to counters used for the service of hot or chilled food.
Counters for hot food are conventionally made of ceramic glass or the like, and are conventionally divided into several sections. Each section may have a separate manual power switch to permit only one or more selected section(s) to be powered up. On start-up, each section receives a power surge until it reaches the required temperature, and then draws power to maintain the surface at a temperature which is often 134 degrees C. This is wasteful if the sections are not in full use over a long period, ie if there are no food containers on the heated sections.
To reduce such waste of power, it is known to provide a beam of radiation close to and parallel to the counter top, as disclosed in DE 87 05 540 U1 Sholl. When food containers are present, the beam is interrupted and power supply is maintained; when there are no food containers on the counter, the beam reaches a sensor and power is disconnected from the heated counter.
In another area of technology, it is known that induction hobs used on domestic and industrial cookers will operate, ie draw power, only when a ferrous container such as a pan is in position on the hob. However, ferrous pans are expensive and are not often used for self-service food containers.